1. Field of the Invention (Technical Field)
The present invention relates to a vibratory plow used for laying pipe and/or electrical cable in the ground.
2. Background Art
Vibratory plows are used to rapidly lay pipe or cable, referred to in this specification as "conduit" below ground at a predetermined depth without the need for first digging a trench into which the conduit is deposited and then covered with the earth that was removed from the trench. Laying conduit underground is used in various power, gas, and telephone utility company applications, but it is also used in the installation of cable TV systems, oil and gas pipelines, and sprinkler systems for industrial, commercial, and residential applications. Particularly in the case of the installation of conduit in residential neighborhoods, it is desirable to operate a vibratory plow that is not of tractor-sized proportions as is typically used in rural areas where conduit must be laid over long distances in rough terrain. A suitable vibratory plow for residential areas is desirably smaller, more maneuverable, and capable of being operated in and among houses, other structures, and trees and other naturally occurring objects without undue harm to such structures and objects.
Many types of vibratory plows are available and have been in use that are more or less directed at the above-identified applications. However, it has been found that most of such prior art vibratory plows are still large, heavy construction equipment that lack the desirable flexibility and maneuverability for laying conduit in confined outdoor environments.
In Applicant's earlier invention as described above, a vibratory plow suitable for the above applications is disclosed, including a plow blade form a "V". The plow machine is shown as a self-propelled vehicle, but it also may be winch-assisted to provide enhanced pulling force when needed for difficult soil conditions or for laying larger conduit. The vibratory plow machine there disclosed includes means for oscillating the V-shaped blade and further the capability of performing the oscillation in a substantially elliptical path or a substantially horizontal path, through manual selection in accordance with the soil conditions. The plow machine included a gasoline engine powering a multi-function hydraulic system, which included powering of the winch, a trans-axle attached to the forward drive wheels that moves the plow machine forward, the above-mentioned oscillating means, a steering wheel, and a hydraulic cylinder operating a blade-extension mechanism that is used to push the V-shaped plow blade into the ground and raise it from the ground upon completion of operations or when an impassible barrier is encountered. The V-shaped plow blade is adapted for laying two parallel conduits, which is desirable in many construction installations. The vibratory plow blade is also capable of adjustment to change the angle of attack.
Notwithstanding the superiority of the above-described earlier invention of Applicant, it has been found that the V-shaped blade configuration used in the described vibratory plow machine is constructed such that the lowest ends or tips of the two blade arms are affixed to a conduit pulling means as shown therein. As a result of the bottom of the V-shaped blade being "closed", i.e., each blade arm attached to the other, there are limitations with respect to the oscillatory paths in which the blade may be operated. As a result of this restriction on the modes of oscillatory movement of the V-shaped plow blade, Applicant has developed an alternative and believed to be more advantageous V-shaped blade configuration.